Is there any chance your son was scammed and that's how this started? There's a scam going around where people specifically look for USAA members and tell them they can deposit a bunch of money into their account and "all they need it that person's online log-in credentials and pin."
Unfortunately, if that's the case, banks don't have legal responsibility in the case of someone getting scammed and giving out their bank account information.
I am happy to hear things are taken care of and sorted out. Trust me when I say, I absolutely understand, so there is no need for apologies. We truly do strive to assist all members, even though the outcome sometimes may not be what the member wishes for. Thank you for keeping us updated, have a Happy Holidays!